Film editing is a critical step in creating a motion picture or television production. A principal consideration in editing a sound motion picture production is synchronizing visual images with their associated sound recording. When a scene is filmed, two simultaneous processes are carried out. A visual image is recorded on motion picture film ("film") by a motion picture camera, and dialogue associated with the visual image is magnetically applied on sound track ("track"). Sound track recording is conducted independently of filming, but generally contemporaneously therewith, and on separate recording apparatus.
As filming of each scene is begun, film cameras and sound recording apparatus are activated. A scene's place in a film is recorded and maintained by the use of the well-known clapper board (i.e., clap board, clapsticks, markers, slates or sticks). A clapper board is used for: 1) visually recording a scene and take number (production company, director, date, etc.) by writing the same (electronically, with chalk, etc.) on the clapper board (or any of several devices performing the same function that are known in the art); 2) providing a precise visual synchronization point on a given scene's film; and 3) providing a precise sound synchronization point on the same scene's track. The latter two functions are accomplished simultaneously when the clapper of a clapper board is snapped shut.
In editing a motion picture for public release, a film editor must edit both film and track. A critical feature of editing is the need for continuous alignment or synchronism of dialogue on track with the visual image on the associated film. The various techniques employed by editors for editing include shifting dialogue forward or backward slightly (overlap/prelap) with respect to an associated segment of a scene. These techniques, as well as others, are well-known to those skilled in the motion picture editing art.
Dialogue is typically recorded during the actual filming of a scene. Often music or some other form of sound is recorded separate and apart from filming of a scene. By way of example, special effects, as well as other effects, are often recorded separately from dialogue. Thus, these sound effects must be mixed with dialogue to complete the track. Typically, dialogue, effects and music are recorded on three separate tracks. However, all three can be mixed onto a one track, e.g., a three-stripe magnetic track or a "full-coat" magnetic track.
Editing of film and track is typically conducted on flatbed film editing machines ("flatbeds"), which have been developed for a number of film formats, including the 35 mm format discussed elsewhere herein. Flatbeds are available in several configurations, including those which are capable of running multiple film and multiple tracks simultaneously during editing. A flatbed typically includes at least one picture display, at least one speaker, reels and controls for moving film and track at various speeds, transducers for reading information contained on film or track, as well as marking and cutting devices as required for movie editing. One such well-known flatbed is the KEM machine.
To facilitate film editing, code numbers are mechanically imprinted every sixteen frames (i.e., one foot on 35 mm movie film) along one edge of film by an editor after the film has been developed. These same numbers are also mechanically imprinted on the track, but only after the recorded sound has been transferred from 1/4 inch magnetic tape used during the filming process to a single-stripe magnetic track (explained elsewhere herein) having perforations ("sprocket holes") corresponding to 35 mm film. The code numbers on the magnetic track correspond to the numbers on the film in the scene at precisely the same point.
Code numbers serve to identify a film's scene number. When used during editing, code numbers indicate the distance from the previously recorded synchronization point as an aid to the editor in finding proper locations for editing. A system of code numbers which is used substantially throughout the film industry is the code imprinted on film and track by the Acmade.RTM. Coding machine, namely, Acmade.RTM. code.
Acmade.RTM. code has seven or eight characters. The first three digits of the Acmade.RTM. code are for scene numbers. A fourth digit is for characters A-E, M, W, P, 1 or blank, which can be used for identifying cameras, music, sound effects, etc. Also, the fourth digit can be used to designate "wild" sound or "wild" tracks. A "wild" track is sound that is recorded without corresponding picture (i.e., thoughts, recall, off-screen dialog, background sound, etc.). The remaining four digits are for current footage in feet from a start mark. Acmade .RTM. code does not provide information for individual frames and/or fractions thereof. A fuller description of coding can be found in Balmuth, Bernard, "Introduction to Film Editing," Focal Press, 1989, ISBN 0-240-51717-2.
Before film editing can begin, synchronism between film and associated track must be initially achieved by matching the first frame of the film (when the clapper closes) with the first modulation of sound (caused by the clapper closing) on track. A synchronizer is a machine known in the art for this purpose. Once synchronism (sync) is achieved, the code numbers previously imprinted along an edge of film are likewise imprinted along an edge of track in the same registration as film. By referring back to code numbers during editing, an editor can approximate those positions on film and track where desired cuts are to be made. This is accomplished by counting forward or backward a given number of frames from the closest Acmade.RTM. code number.
In the past, a film editor was expected to synchronize dialogue on track with scenes on film by judging the action on film with dialogue on an associated track. An editor would accomplish this task by referring back to Acmade.RTM. code numbers, imprinted every foot along the edges of film and track to estimate proper positions on them for editing. The correct position for editing the track must be estimated because, unlike film, track is not visually differentiated into frames.
In the motion picture arts, dialogue is often mixed (dubbed) with sound effects and music after the editing is completed. This dubbing complicated the previously discussed problem of synchrony between picture and sound. Film must be in synchrony with track before and after dubbing. In the motion picture arts, track used for dubbing is called a one-to-one track. A one-to-one track is used for combining or dubbing dialog, music and sound effects from each of their respective original recordings. Additionally, when dialogue, effects and/or music are dubbed onto a full-coat magnetic track, it is incumbent upon an editor to synchronize the information on that track with associated film. In the past, the editor performed this task in a trial and error manner as previously described.
This trial and error process lacks precision and is very time consuming. In the past, there was no practical, convenient means to precisely synchronize track with film images on a frame-by-frame basis while cutting and splicing track and film during editing. A means whereby track and film could be maintained in synchronism throughout editing would obviate the need for the trial and error re-synchronization process of the prior art. Moreover, by removing the burden for this iterative trial and error re-synchronization between film and track during editing, significant time and cost savings would necessarily accrue.
Some of the problems associated with traditional film editing as previously discussed were alleviated with the advent of videotape technology. Videotape editing provided significant cost reductions over earlier practice. Prior to videotape, initial editing was done directly on film as previously discussed. Videotape editing technology enables a high degree of automation to be applied to editing. Using well-known videotape recording systems (VHS, Telecine, Rank-Cintel, among others) film and track are copied to videotape. These taped images and dialogue are then edited electronically.
Currently available videotape editing systems include recording and playback machines, video inserters, monitors, address generators, keyboard control consoles and associated electronics. This equipment enables an editor to repeatedly try an edited version of a scene until the desired effect is achieved. As all image transfers are accomplished electronically, videotape is not actually cut or spliced, and significant convenience and editing economies are thereby achieved. Videotape technology can record simultaneously on videotape a given film's visual image, dialogue of the film's synchronized track and videotape addresses generated by the videotape editing system. These videotape addresses are subsequently used for editing the videotape.
Rather than actually physically cutting videotape for editing, the data recorded thereon is electronically manipulated. As is well-known in the art, as an editor makes editing "cuts" in videotape, "cut" data or addresses are stored, typically by video recorder/player. When an edited videotape version of a scene has been completed, the videotape address for each required cut is written to an edit decision list. This edit decision list is then used as the basis for editing one version of videotape.
The ability to electronically edit videotape as previously discussed does not enable film and track to be likewise edited with a high degree of automation. Film and track must be cut and spliced as previously described to reflect the editing previously done on the videotape version of the scene. Therefore, when an editor has completed editing on videotape, the edit decision list cannot be used to edit film and track. There is no convenient means for transferring addresses associated with videotape back to film and track for editing.
The videotape frame addresses do not refer to film frames and are therefore of no utility in film editing. For example, once videotape editing is completed, there is no means (other than the trial and error visual and sound process previously discussed) to synchronize dialogue on track with images on an associated film on a frame by frame basis. Further, videotape is generally recorded at 30 frames per second while film is photographed at 24 frames per second (90 feet per minute). The difference between the recording rates of track and film on one hand and videotape on the other cause videotape reference addresses to be unusable for editing film and track.
Therefore, the editor must visually locate the corresponding scene on film based on the video image, and find the closest Acmade.RTM. code which was imprinted on the film and track. Film and track are then cut and spliced, referring to the Acmade.RTM. code numbers imprinted on both. To accomplish this, the editor visually locates a specified Acmade.RTM. code on both the film and track. This Acmade.RTM. code provides a rough location for the required cuts (recalling that Acmade.RTM. code is imprinted only once per foot of film and track). An editor must precisely locate the given film frame and its associated track section using the flatbed to synchronize the dialogue on track with images on film, in the manner previously discussed herein. Once the exact location for a given cut is found, the splice is finally effected in a manner well-known in the art. Again, this iterative process must be repeated for every edit cut in a given motion picture.
Efforts by other inventors have resulted in several methods, products and apparatus for encoding frame data for editing film. While extremely useful for film editing, they do not address the more complex problem of locating, on a separate and otherwise undifferentiated medium (i.e., track), an exact location for making an edit cut with respect to its corresponding location on film.
In current practice, commercial motion pictures are typically initially filmed on 35 mm motion picture film. This well-known photographic medium consists of a transparent flexible substrate (such as acetate or plastic), 35 mm wide, having a row of rectangular perforations ("sprocket holes") with dimensions of approximately 2.times.3 mm equally spaced approximately 3 mm apart and disposed continuously 2 mm from each edge of film for providing four sprocket holes on each side per frame ("four-sprocket frame"). Film substrate is typically coated with one of several well known photographic emulsions for recording visual images.
The physical dimensions of track's flexible substrate is similar to 35 mm motion picture film. For editing, a single-stripe magnetic track is used. However, in place of photographic emulsion, single-stripe magnetic track has two stripes of magnetic recording material suitably disposed thereon.
One stripe (a "sound track" or "single stripe") is actually used to record dialogue of a scene being filmed, and is typically 8 mm in width. Another stripe, (a "balancing band" or "balance stripe"), is typically 5 mm wide.
The track's single stripe is not positioned centrally on its substrate in order to properly align the single stripe with the sound recording head currently in use. Because the single stripe is positioned off-center on substrate, long coils of track on reels become mechanically unstable. This is due to the thickness of magnetic recording material added to substrate. An unstable roll would tend to become uncoiled during editing, especially from the open reels in common use. Also, level contact with a sound head provides the best quality of sound recording. To maintain level contact and to mechanically stabilize the roll, the balance stripe is used. For these reasons, and as the name implies, a balance stripe (which is identical in thickness and composition to single stripe) is applied to track.